Motor-operated compressor

Abstract

An electric compressor includes a first scroll and a second scroll engaged with the first scroll and making an orbiting motion to form a pair of two compression chambers with the first scroll. A rotary shaft is eccentrically coupled to the second scroll and is rotatably supported by a bearing member. A frame is fixed to an opposite side of the first scroll from the second scroll with the second scroll being interposed between the frame and the first scroll. The frame includes a bearing support portion, and the bearing member is inserted into and fixed to the bearing support member with an interference fit.

What is claimed is: 
     
         1 . An electric compressor comprising:
 a first scroll;   a second scroll engaged with the first scroll on a first side of the first scroll, the second scroll being configured to make an orbiting motion relative to the first scroll to form a pair of two compression chambers with the first scroll;   a rotary shaft eccentrically coupled to the second scroll;   a bearing member rotatably supporting the rotary shaft; and   a frame fixed to an opposite, second side of the first scroll with the second scroll interposed between the frame and the first scroll, the frame including a bearing support portion, and the bearing member being inserted into the bearing support portion and fixed to the bearing support portion,   wherein an inner diameter of the bearing support portion is smaller than an outer diameter of the bearing member before the bearing member is inserted into the bearing support portion.   
     
     
         2 . The electric compressor of  claim 1 , wherein
 the inner diameter of the bearing support portion is 0.08% to 0.13% smaller than the outer diameter of the bearing member before the bearing member is inserted into the bearing support portion.   
     
     
         3 . The electric compressor of  claim 2 , wherein
 the frame comprises a material having a thermal strain temperature lower than a thermal strain temperature of the bearing member or a thermal strain temperature of the rotary shaft.   
     
     
         4 . The electric compressor of  claim 3 , wherein
 the bearing support portion includes a guide surface, and an inner diameter of the guide surface of the bearing support portion increases in a direction in which the bearing member is inserted into the bearing support portion.   
     
     
         5 . The electric compressor of  claim 4 , wherein
 an axial length of the guide surface is ½ or less of an entire axial length of the bearing support portion.   
     
     
         6 . The electric compressor of  claim 1 , wherein
 a pressure of a refrigerant discharged from at least one of the pair of compression chambers is 100 bar or greater during operation of the electric compressor.   
     
     
         7 . The electric compressor of  claim 6 , wherein
 the frame comprises aluminum material.   
     
     
         8 . An electric compressor comprising:
 a first scroll;   a second scroll engaged with the first scroll on a first side of the first scroll, the second scroll being configured to orbit relative to the first scroll to form a pair of two compression chambers with the first scroll;   a rotary shaft eccentrically coupled to the second scroll;   a frame fixed to an opposite, second side of the first scroll with the second scroll interposed between the frame and the first scroll and the rotary shaft penetrating through a portion of the second scroll;   a bearing support portion formed in the frame; and   a bearing member inserted into the bearing support portion and disposed between the frame and the rotary shaft or between the second scroll and the rotary shaft and rotatably supporting the rotary shaft,   wherein an outer diameter of the bearing member is 0.08% to 0.13% greater than an inner diameter of the bearing support portion before the bearing member is inserted into the bearing support portion.   
     
     
         9 . The electric compressor of  claim 8 , wherein
 a shaft hole through which the rotary shaft penetrates is formed in the frame on one side of the bearing support portion, and a sealing member is disposed in the shaft hole to seal a gap between an inner circumferential surface of the shaft hole and an outer circumferential surface of the rotary shaft.   
     
     
         10 . The electric compressor of  claim 9 , wherein
 the sealing member is formed of a material having a coefficient of thermal expansion that is larger than with a coefficient of thermal expansion of the frame.   
     
     
         11 . The electric compressor of  claim 8 , wherein
 the frame comprises aluminum and the bearing member comprises steel.   
     
     
         12 . The electric compressor of  claim 11 , wherein
 in a state in which the bearing member is press-fit into the bearing support portion, an inner diameter at a corner of the bearing support portion is the same along a circumferential direction.   
     
     
         13 . The electric compressor of  claim 11 , wherein
 in a state in which the bearing member is press-fit into the bearing support portion, an inner diameter at a corner of the bearing support portion is the same as an outer diameter of the bearing member along the circumferential direction.   
     
     
         14 . The electric compressor of  claim 8 , wherein
 a pressure of a fluid discharged from at least one of the pair of compression chambers is 100 bar or greater during orbiting motion of the second scroll relative to the first scroll.   
     
     
         15 . An electric compressor comprising:
 a frame;   a fixed scroll fixed to the frame;   an orbiting scroll engaged with the fixed scroll, the orbiting scroll being configured to make an orbiting motion relative to the fixed scroll to form a pair of two compression chambers with the fixed scroll;   a rotary shaft eccentrically coupled to the orbiting scroll; and   a bearing member rotatably supporting the rotary shaft, wherein   the orbiting scroll is interposed between the frame and the fixed scroll, the frame includes a bearing support portion, the bearing member is inserted into the bearing support portion and fixed to the bearing support portion, an inner diameter of the bearing support portion is smaller than an outer diameter of the bearing member before the bearing member is inserted into the bearing support portion, and the bearing support portion includes a guide surface along a portion of the inner diameter of the bearing support portion with an inner diameter of the guide surface increasing in a direction in which the bearing member is inserted into the bearing support portion.   
     
     
         16 . The electric compressor of  claim 15 , wherein
 the inner diameter of the bearing support portion is 0.08% to 0.13% smaller than the outer diameter of the bearing member before the bearing member is inserted into the bearing support portion.   
     
     
         17 . The electric compressor of  claim 16 , wherein
 the frame comprises a material having a thermal strain temperature lower than a thermal strain temperature of the bearing member or a thermal strain temperature of the rotary shaft.   
     
     
         18 . The electric compressor of  claim 17 , wherein
 the bearing support portion includes a guide surface, and an inner diameter of the guide surface of the bearing support portion increases in a direction in which the bearing member is inserted into the bearing support portion.   
     
     
         19 . The electric compressor of  claim 18 , wherein
 an axial length of the guide surface is ½ or less of an entire axial length of the bearing support portion.   
     
     
         20 . The electric compressor of  claim 15 , wherein
 a pressure of a fluid discharged from at least one of the pair of compression chambers during operation of the electric compressor is 100 bar or greater.